Julian Brazier, Tory MP for Canterbury and President of the Conservative Family Campaign, declared that the controversial Bill was worth passing for "this single item alone".
The amendment, due to be approved next week, will allow judges to withhold or delay a divorce where it would cause substantial financial or other hardship to a spouse or any children and it would be wrong in all the circumstances including the conduct of the parties and the interests of any children.
Mr Brazier said: "This is the most important shift towards the interests of the child for a generation."
It is expected that the views of children would normally be recorded in welfare reports rather than through evidence to the court.
The MP said the change would mean that for the first time courts would be able to look at factors such as the person with whom a parent was proposing to live.
Lord Mackay made clear yesterday that the provision would only be invoked in very exceptional cases.
As rebel Tory peers prepared for a fresh onslaught on the Bill's main provisions for no-fault divorce after one year, the Government took the highly unusual and probably unprecedented step of appointing a Lord Chancellor's parliamentary private secretary, Peter Luff, the MP for Worcester.
Mr Luff, who recently promoted a 10-minute rule Bill urging minimum ages to be displayed on teenage girls' magazines, will work closely with Jonathan Evans, a junior minister, who is a solicitor and Catholic, in keeping the lid on rebellions when the controversial Bill reaches the Commons at the end of next month.
The appointment comes amid Tory misgivings over the Government's embarrassment at having to rely on Labour and the Liberal Democrats to get the legislation through.
Baroness Young, the former Tory minister leading the rebellion, is pressing for fault-based divorces to be retained and for the 12-month period of "reflection and consideration" to be lengthened to 18 where the couple has children.
Lord Mackay is opposed to such a change the grounds that it could be more, not less, damaging to children, while business managers say making a concession along those lines to Lady Young and her supporters would cost Labour backing.
The Government meanwhile confirmed its intention to issue a Green Paper on so-called "pension splitting" in response to amendments to the Bill from Labour's Baroness Hollis.Reuse content