Calls to the housing charity Shelter have surged 40% as rising living costs and welfare cuts leave growing numbers of people struggling to pay their bills.

The charity said in the past year its helpline dealt with 12,408 callers in England who wanted assistance with housing costs, arrears and other debt problems – up from 8,838 in 2011-12. In the past six months unique visits to its online advice page had doubled, it added.

A series of welfare changes took effect this month, including a £26,000 a year cap on household benefit claims, which began on 15 April in four London boroughs and will be implemented nationwide from 15 July, and the so-called bedroom tax, which will result in social housing tenants losing 14% of their housing benefit if they are deemed to have one spare bedroom, or 25% if they are deemed to have two.

Shelter said with further benefit cuts on the way, it was concerned that "even more people will be left desperately trying to find the means to pay for their home".

The charity published research which it said showed that those who were struggling to pay their rent or mortgage had few options for increasing their income, with only 21% saying they or their partner were able to get extra hours at work and only 26% saying they could get a second job. Last month Shelter reported that almost a third of people had already cut back on food to pay housing costs.

It has launched an advice-sharing day called Pass It On to raise awareness of the importance of getting help early to help prevent people from losing their homes. It is urging Facebook and Twitter users to share messages about Shelter's free housing advice, which helps people prioritise and manage housing debts, negotiate with lenders or landlords and improve their budgeting skills. For more information visit shelter.org.uk/advice