The government has reversed its position on moves to strip charities and medics of their exclusive responsibility for counselling women seeking an abortion, saying it will now advise MPs to vote against proposals from a Conservative backbencher if they are put before the Commons next week.

The U-turn from the Department of Health came after Downing Street intervened in the row that arose when Nadine Dorries, the Tory MP for Mid Bedfordshire, tabled an amendment to the health and social care bill that would mean all women seeking an abortion were offered advice independent of the abortion provider. The government will continue to consult about ways to improve counselling services for women seeking a termination but the results are no longer a foregone conclusion.

Downing Street sources said that David Cameron, Nick Clegg and other senior members of the government would vote against the Dorries amendment.

The Department of Health had previously said that new "independent" counselling was a certainty.

The U-turn, stemming from No 10's frustration about the health department's handling of the situation, is another embarrassing blow for the health secretary, Andrew Lansley.

The Dorries amendment, if approved, could sideline abortion charities such as the British Pregnancy Advisory Service and Marie Stopes International, and leave the system in disarray.

Dorries claims the charities face a conflict because they both provide counselling and are paid to provide abortions, that her proposal would reduce abortions by a third, and that an alternative offer would prevent women being rushed into abortions that they may later regret. Pro-choice campaigners say this could delay abortions and strip abortion services of their ability to provide counselling.

On Sunday, in an apparent attempt to placate Dorries's growing number of backbench supporters and avoid the amendment dominating next week's parliamentary debate, the Department of Health said it wanted to introduce an offer of independent counselling, separate from the abortion providers, promising to consult on how best to do it.

An aide to Lansley confirmed that the move was partly in response to Dorries's proposals, triggering accusations that the government was caving in to the anti-abortion lobby, which has backed the move. Senior Liberal Democrats were incensed. No 10 sources said Cameron was supportive of the idea that all women should be offered a choice of counselling but had become concerned at the idea that existing charities might be relieved of their responsibilities and so would now vote against the motion.

"The prime minister believes that women should have a choice, a proper choice, not any one selective group of organisations," the source said.

After No 10's intervention, the Department of Health said there would be a consultation on the "best" form of counselling for women. "The discussions currently under way do not represent any moral shift in the government's approach to abortion as an issue, and there are no changes to the Abortion Act involved," it said. "Instead the concern is to ensure that women, in what is an extremely difficult and often traumatic situation, have access to information and counselling that best meets their needs. We will continue to discuss this with all involved in the debate. We plan to consult widely on these proposals later this year."

If the amendment is selected next week, it will be a free vote for MPs, as is the tradition with the most controversial "matters of conscience". But coalition MPs will be steered to vote against it. It is understood that the prime minister, the health ministers and other senior members of the government will vote against. Labour has adopted a similar position.

But a combination of the unpredictable intake of new Tory MPs, split between social conservatives and modernisers, the number of Roman Catholic Labour MPs, and the high degree of nuance of the amendment make it extremely unclear which way the vote will go.