Boris Johnson has been accused of "hiding" following the flooding crisis across England and Wales.
Speaking at Prime Minister's Questions, Labour leader Jeremy Corbyn branded Mr Johnson a "part time prime minister" who "goes Awol" during emergencies.
Mr Johnson said the government was working "flat out" to help people.
Challenged that the government had not acknowledged the scale of the problem, he said the government had a "fantastic record" in investing in flood defences.
Mr Corbyn quoted Barry Lewis, the Conservative leader of Derbyshire County Council, who was among several local authority leaders to demand easier access to emergency funds.
Mr Lewis told The Guardian: "We are not very happy. You can't give local authorities the clear message you are going to support them and then turn your back on them."
Mr Corbyn said the amount the government wants to spend on flood defences is "less than half" the £5.6bn deemed necessary by the Environment Agency for England.
"The Welsh government have done their best to step up to the crisis despite the under-funding from Westminster," the Labour leader added.
And he said Mr Johnson should go and visit affected homes, as he had done in Wales - and should find an "urgent solution" to the problems created by insurance claims.
Mr Johnson said the government is looking at what can be done to compensate people who do not have "proper insurance".
He said measures are already in place to ensure people can claim £500 or £5,000.
He added: "The reason the government had been able to commit £2.6bn to flood defences - and we are able to pledge another £4bn - is because this government is running a strong and successful and robust economy, which he would ruin."
Mr Corbyn claimed the PM "often goes AWOL", referring to the London riots when Mr Johnson was London mayor, adding: "How can this country trust a part-time prime minister?"
He asked why Mr Johnson had not called a Cobra meeting to discuss flooding since the general election campaign.
The PM said: "Cobra is a reference to Cabinet Office Briefing Room A. It is not the only room in which meetings can take place."