Indian e-commerce giant Flipkart has raised another $3.6bn (£2.6bn) ahead of an expected stock market debut.

The Walmart-backed company said it will use the money to expand its operations and invest further in its grocery, fashion and delivery service.

The latest round of fund-raising increased the firm's value to $37.6bn.

The new valuation is more than double the amount the American retail chain paid for a majority stake in Flipkart three years ago.

Flipkart's chief executive Kalyan Krishnamurthy said the new funds would support the company's expansion plans: "As we serve our consumers, we will focus on accelerating growth for millions of small and medium Indian businesses."

"We will continue to invest in new categories and leverage made-in-India technology to transform consumer experiences and develop a world-class supply chain," Mr Krishnamurthy added in a company statement.

The new round of funding was led by Singapore's sovereign wealth fund GIC, the Canada Pension Plan Investment Board, Japan's SoftBank and Walmart.

The deal marks the return of SoftBank, which sold its stake of around 20% of Flipkart to Walmart as part of the 2018 deal.

Other investors included sovereign wealth funds from Malaysia, Qatar and Abu Dhabi.

The fund-raising came as the Bengaluru-based company is expected to make its stock market debut as early this year.

In 2018, Walmart paid $16bn for a 77% stake in Flipkart and said later said that it could take the company public within four years.

In September, the Reuters news agency reported that Flipkart was preparing for an initial public offering outside of India as early as this year, in a move which could value it at as much as $50bn.

Since the Walmart deal the company has added many more items to its online store, including groceries and furniture.

Flipkart has also increased its warehouse capacity as it battles competition from Amazon's Indian operation and local rival Reliance Industries, which is owned by Asia's richest person Mukesh Ambani.

India has seen huge growth in online start-ups, selling everything from groceries to holidays, which has been driven by the rapid adoption of smartphones and cheap mobile data deals.

Several of the country's biggest digital start-ups are already on track to sell shares on the stock market.

India's biggest food delivery app Zomato is due to make its debut this month, while payments service PayTM is expected to launch its initial public offering by the end of the year.