The Coalition’s political fortunes remain in the doldrums seven weeks on from the conservative-led coup against Malcolm Turnbull, with two new opinion polls indicating that Labor would comfortably win any election held today.

With federal parliament resuming on Monday, both the Newspoll and the Ipsos polls published on Sunday night have Labor well in front of the government on the two-party-preferred measure, 53% to 47% and 55% to 45%.

Those results are consistent with the last two Guardian Essential polls, where Labor was ahead 53% to 47%.

The decision by the Liberals to dump Turnbull from the prime ministership and install the former treasurer Scott Morrison triggered an immediate slump in the opinion polls, which is unusual, given that past leadership changes have given the government of the day a bounce.

Almost two months after the upheaval, the negative voter sentiment shows no sign of abating.

There are two comforts for the government in the sustained negative trend. Morrison is preferred as prime minister over the Labor leader, Bill Shorten – who marked five years as opposition leader at the weekend – and the Liberal party’s primary vote has rebounded in the Newspoll by four points since the leadership upheaval.

Morrison has endured a difficult week, with the leaking of the Ruddock review on religious freedom, rising public concern about deteriorating conditions on Nauru, and renewed debate about climate change triggered by the release of a report from the world’s leading climate scientists warning that there are only a dozen years to act if global warming is to be kept to a maximum of 1.5C.

The prime minister faces a significant test on Saturday, when the Liberals are attempting to hold Turnbull’s Sydney seat of Wentworth at a byelection, with several seat polls pointing to a strong protest vote against the government.

Uncomfortably for Morrison, climate change and Nauru have been significant local issues during the Wentworth contest, and the leaking of the Ruddock review was also a blow, given that the government had planned to respond to its recommendations only after one of Australia’s most socially progressive electorates had returned its verdict.

Morrison has attempted to warn voters in Sydney’s eastern suburbs against generating a boilover that would cost the government its one-seat majority in the lower house.

“Whatever concerns you may have about events of several weeks ago, if you don’t vote for the Liberal candidate, then you risk a hung parliament,” the prime minister said at the weekend. “You risk creating unnecessary uncertainty in our economy and the stability of our government more broadly.”

A furious public debate was triggered last week about one of the Ruddock review proposals to amend the federal Sex Discrimination Act to provide “that religious schools may discriminate in relation to students on the basis of sexual orientation, gender identity or relationship status”.

The new Ipsos poll, published by Fairfax, indicates that 74% of voters are opposed to such a provision, including 62% of Coalition voters. The poll suggests only 30% of Coalition voters back the right of religious schools to discriminate against gay students and teachers.

To contain the furore, Morrison has now promised discrimination law amendments to make it clear that no student at a private or religious school should be expelled on the basis of their sexuality. The changes are expected to be debated by the government party room this week.

The prime minister said on Sunday he did not envisage controversy inside the government over the changes he now proposed: “I’ve only had strong messages of support from my colleagues.”

His objective, he said, was to get the reforms agreed in the next fortnight. “I hope we can do that without a whole bunch of posturing and hoopla,” he said.