Commuters faced delays for a fourth day on Monday even as the city state's government laid on extra buses to help them to get to work after most drivers stopped taking bookings via the smartphone apps that connect them to nearby passengers.

It was the first big confrontation between trade unions representing taxi drivers in the Delhi region of 25 million people and the two ride-hailing players, which have been ramping up services in India's $12 billion taxi market.

Both Uber and Ola faced disruptions, with their apps showing 'no cars available' when attempts were made to book a ride near Connaught Place in the city centre during the day.

Uber later won an injunction in the Delhi High Court against two taxi unions that backed the strike to prevent what the company described as intimidation of its so-called driver partners, most of whom are private car owners and are not unionised.

The court order restrained the unions from stopping Uber drivers, removing devices from their cars or otherwise hampering them, according to a copy of the ruling the company released to Reuters.

"We welcome this court order, which prohibits unions, their leaders and anybody else from obstructing the activities of Uber driver partners as they go about their business," Uber said in a statement.

"We hope it will enable drivers to get back behind the wheel, something many have been telling us they wish to do. We're sorry that our service has been disrupted and for any inconvenience this has caused."

Ola did not respond to requests for comment.

Strike leaders earlier said that they were demanding an increase in incentives, provision of adequate insurance policies and shorter working hours for drivers.

"These companies are cheating us. They do not pay us on time and expect us to work like slaves," said Jatindra Singh, a senior member of the New Delhi Taxi Union. Singh said 35 unions representing nearly 4,000 drivers were backing the strike.

San Francisco-based Uber has focused on India as its most promising market outside the United States since it merged its Chinese operation into market leader Didi last year. It operates in 28 Indian cities and has 200,000 active drivers.

Homegrown rival Ola calls itself India's most popular mobile app for transportation. It is present in 102 cities and offers rides in 450,000 vehicles.

The ride-hailing players face resistance from traditional, unionised taxi services and three-wheeler auto rickshaws, whose standard fares they are undercutting. Taxi drivers and private "driver partners" often use both platforms to solicit rides.

Delhi's Transport Minister Satyendar Jain ordered an increase in the frequency of bus services to help commuters get to work and planned to meet striking drivers on Tuesday in a bid to end the dispute.

"I am going to hear all the sides and then we will set new rules soon," he told Reuters.