Some of the UK's leading law firms are having to push back their long-awaited launches in Abu Dhabi due to delays in receiving their licences from local authorities.

The move comes as growing numbers of firms rush to the region amid increasing pressure from local clients, including coveted sovereign wealth funds, to launch offices in Abu Dhabi as well as Dubai.

Clifford Chance (CC), Ashurst and Herbert Smith are among the firms still waiting to receive clearance to open branches in the emirate, with a host of major UK firms targeting expansion there.

Richard Ernest, who will head CC's Abu Dhabi branch which was originally scheduled to open in April, commented: "Everything is in place and we are just waiting for the regulatory steps. We are looking to launch later this year – I do not know exactly what date."

DLA Piper is also still waiting for its licence. Co-chief executive Nigel Knowles said: "I believe the licence is likely to be approved in the next few weeks, but it depends on when the authorities have time to look over it. The opportunities are good and we are committed to the Gulf region."

News of the delays comes as a clutch of major commercial practices pour money into opening multiple Middle East branches.

In addition to its planned Abu Dhabi launch, DLA Piper last year unveiled plans to open in Qatar, while earlier this month Latham & Watkins announced its intention to open in three locations in the Middle East.

The firm is set to open in Dubai, Abu Dhabi and Doha, with corporate partner Rindala Beydoun coming in from Vinson & Elkins to spearhead the firm's development in the region.

Explaining the need for firms to open multiple offices, Knowles told Legal Week: "If you want to establish a good relationship with the companies and authorities in Abu Dhabi you need to set up a local office. You can only really expect to work with them if you are prepared to invest in Abu Dhabi itself."

Other lawyers say the intense regional rivalry within the Middle East region is forcing firms to set up Abu Dhabi branches.

The local head of one major firm confirmed the problems saying: "Abu Dhabi clients expect law firms to be in Abu Dhabi and will not use firms based in Dubai due to political rivalry."

Another leading partner in the region said: "Dubai is very close, so the reality is that our lawyers are travelling between the two cities. We do not really distinguish between the two offices, but you have to have a certain number of lawyers based in Abu Dhabi [to obtain a licence]."

Other firms to have opened in Abu Dhabi recently include Allen & Overy, White & Case and Vinson & Elkins.