The restriction levels will return to level 1 on March 1 once the water is deemed to have met the high quality standards set, The Sydney Morning Herald reported.
"We recently experienced the biggest rain event in 20 years which has impacted the quality of water in the Greater Sydney Catchment", Pavey told The Daily Telegraph.
She said the delayed implementation of water restriction relief would allow more time to assess changes in water quality.
"A number of initiatives are in place to ensure the water is safe for use, including extensive testing, filtration and nets to catch debris".
But NSW Greens MP Cate Faehrmann said it was hard to know the impact in two weeks' time of less oxygen in Warragamba Dam.
The NSW Cabinet has approved changes to soften water restrictions to level one in greater Sydney from March..
"It's grossly irresponsible for the water minister to wind back restrictions now for a good news headline while there are still serious risks around the future viability of Sydney's water quality", Ms Faehrmann said in a statement.
Heavy rainfall commonly pushes sediment and debris into Lake Burragorang (Warragamba Dam), however the addition of unprecedented amounts of bushfire ash and the lack of ground cover to prevent soil erosion has resulted in increased levels of debris making its way into the lake.
The rainfalls have also brought a much-welcomed boost to the country's dam reserves.
There remains some concern that the rain may have washed ash and other debris from the recent bushfire disaster into the catchment area, causing contamination, with officials closely monitoring water quality.
But after last weekend's rainfall - the heaviest in 20 years - the dams are now at 80 per cent capacity.
Residents in the state will now be able to use hoses, though they will need to be fitted with a control nozzles to ensure supplies are not exhausted too quickly, the state government said.
Individuals found to be breaking the restrictions could face fines of $220.
Level two restrictions, which prohibit hosing the garden or washing a auto, were implemented across Sydney on December 10.