Economic migrants coming to Britain should be treated with the same sympathy as refugees fleeing war, Diane Abbott has said.

The shadow international development secretary also said it is wrong and racist to claim, as some of her colleagues in the Labour party had done previously, that eastern European immigrants were the cause of wage cuts for English workers.

Abbott was speaking on Thursday at an event to welcome refugees in north London also attended by the Labour leader, Jeremy Corbyn.

The refugee and immigration issue is likely to be controversial as Labour seeks to defeat a Ukip challenge in next month’s Oldham West byelection, triggered by the death of Michael Meacher.

She said: “I would remind you, thousands of people crossing the Sahara, risking their lives in the Mediterranean, coming over the Balkans, are also economic migrants and we do not want to fall into the error of thinking that refugees are in some sense a class of migrant more deserving of our sympathy.

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“Just as our hearts goes out to Syrians struggling, dying, suffering and drowning, our hearts should also go out to economic migrants in Nigeria, Eritrea and north Africa, struggling, drowning and suffering. Economic migrants are not a lesser cause.”

She said the migration crisis had been caused by problems such as climate change and instability, but “above all there are issues with a series of ill-fated western interventions in Libya, Syria, Iraq and across the Middle East”. The European Union is predicting that there will be as many as 3 million refugees arriving in Europe next year.

Without naming any individual, Abbott also criticised “those in the Labour party that seem to want to argue that immigrants are in some sense the cause of our economic woes”. She said: “This is something I deplore. Immigrants in and of themselves do not cause low wages. Predatory employers, deregulated labour markets and weakened trade unions – they cause low wages.”

She argued that some people, including members of the Labour party, wrongly contend that the current debate about immigration is not about race by pointing to the fact that eastern Europeans are white.

Abbott said: “I would refer them to the toxic anti-Irish racism of the 19th century – the way the Irish were dehumanised and caricatured. Every single allegation made against the eastern Europeans – they were undercutting local labour, they were driving down wages, that they were the cause of the problems of the English working class – every single allegation that you hear made against eastern European migrants today, they said about the Irish in the 19th century. It was wrong then and it is wrong now.”

The government’s response to the crisis was inadequate because the refugee conversation had been poisoned by the toxic debate about immigration year after year, she said.

Abbott added that it was hypocritical of neoliberals to wring their hands about the effects of eastern Europeans on wages, since it was the liberalisation of labour markets and the weakening of trade unions that were the real culprits.

She described Corbyn as “the first authentically leftwing leader of the Labour party in a generation”.

Speaking at the event, Corbyn said his success in the Labour leadership election showed “the politics of me, not we, are over”. “It was a victory not for me, but for all those that want to see a different, better and more peaceful world,” he said.

He called on Britain to “hold out the hand of humanity and not brutality to refugees. I do not use the language of swarm and swamp and all those things. I look at those people as fellow human beings, just like you, just like me, just doing their best to survive in a cruel and dangerous world”.

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Corbyn said David Cameron’s pledge to take in up to 20,000 Syrian refugees over five years was inadequate, pointing to the hundreds of thousands being granted asylum by Germany and urging the government to assist local councils in giving a place of safety to refugees in the UK.

He insisted he held no brief for those fighting in Syria, and said he only wanted peace in the region. “Further bombing, further interventions, further boots on the ground, further wars is not going to solve the problem. All wars have to end by a political solution,” Corbyn added.

Without specifying how many refugees the British government should take, the Labour leader pointed out that Germany has taken hundreds of thousands of refugees and Britain should be doing more.

He said: “Refugees should not be treated as a problem, a threat, a difficulty and somehow or other to be confronted and kept out.

“The problem across Europe will not be solved by the construction of razor-wire fences around countries, by having gun boats in the sea and by having electronic surveillance and tagging of people all across the world that are trying to achieve a place of safety.”

The solution lay “in greater equality and above all by ending the series of wars that have disfigured this century so far,” Corbyn added.