The new Sydney Olympic Park master plan is also expected to fuel development that will see western areas of Sydney eclipse eastern and northern neighbours.

According to a new report by PricewaterhouseCoopers (PwC), Parramatta's economic growth is set to almost double over the next five years and the city is on track to become a leading financial hub

The Parramatta 2021 report, commissioned by the City of Parramatta, found the economy of Sydney's dual CBD will grow by $7 billion by 2021, to $30 billion.

City of Parramatta interim general manager Greg Dyer said that within five years it is forecast that an additional $1.2 million will be spent on retail each day by workers, residents and visitors in Parramatta and commercial floor space is set to increase by more than one-third compared to current levels, with an additional 232,000 square metres to become available in the next five years.

"As one of the largest CBDs in Australia Parramatta is already a significant economic hub and a major employment and retail centre, and the completion of projects such as Parramatta Square will take our city to the next level," Mr Dyer said.

Retail giant Scentre Group, as first revealed by Fairfax Media, is to develop a 40-storey, 100,000 sq m office tower atop its Westfield Parramatta shopping centre, while DEXUS Property and developer Lang Walker also have significant projects in the city core.

Parramatta City Council also recently selected Woods Bagot's design for Coronation Property's "8 Phillip Street" – a 54-storey building with 35 levels of apartments, a proposed five-star hotel and rooftop bar – that  will integrate with the existing heritage St Andrew's Church and St Andrew's hall.

The projects come as the prime office vacancy rate has been recorded as zero.

Parramatta's total vacancy measured 4.5 per cent as at July 2016, substantially below the 10 year average of 8.3 per cent, while prime vacancy was 0 per cent – the lowest prime vacancy rate across all Sydney office markets.

According to Knight Frank's latest research report Parramatta Office Market Brief: September 2016, the Parramatta market is expected to undergo significant rejuvenation over the next five years as substantial developments reach completion.

Knight Frank research analyst Bradley Rehn said the generation of new supply expected in the short-term is largely underpinned by Stage 1 Parramatta Square in 2016, as well as DEXUS' 105 Phillip Street site in 2018.

"Further developments, including Parramatta Square stages 3, 4 and 6, Westfield and 127 Argyle Street are expected over the next five years," Mr Rehn said.

Knight Frank's Tom Bartlett, director, office leasing, said activity in the prime market is currently defined by the zero vacancy status of A-grade stock.

"As a result, the secondary market has experienced heightened leasing activity over the 12 months to July 2016, with occupied space increasing by 14,398 sq m," Mr Bartlett said.

Investment dollars are also flowing in, according to Knight Frank's director, commercial sales, Wally Scales, who said the most recent transaction, an A-grade building at 18 Smith Street, sold for $84.75 million.

"Investor demand still remains high, with the Transport NSW building and Salvation Army sites on the market, which will be presented for further office development," Mr Scales said.