Earlier today, the Financial Times reported that negotiations between the two parties had stalled and the chances of a deal being completed were diminishing.
However, a source close to the situation told Reuters that both sides are "fully engaged", with discussions "in full swing".
"In any negotiation there are issues that need to be solved and they will take time," the person was quoted as saying.
The sale relates to some of RBS's operations in China, India and Malaysia and talks are ongoing in all three locations over a transaction that is likely to cost Standard Chartered up to $200 million.
Retail and small business operations are believed to be the target for Standard Chartered, which has a large presence in Asia.
The Financial Times had previously cited sources close to the matter as saying that the chances of RBS and Standard Chartered reaching an agreement had dropped to "around three out of ten".
According to the publication, talks relating to the sales of Chinese assets were "in limbo", with Standard Chartered believed to be disappointed that there were more RBS customers locked in to specific products than it had expected, meaning it would be difficult to move them to alternative packages following an acquisition.
This was believed to relate to RBS's assets in China, which the bank is looking to sell quickly in order to implement a new regional strategy focusing on wholesale clients.
The newspaper noted that discussions between the two parties began last month, with Standard Chartered hoping to have a deal secured "within weeks".
Earlier this month, RBS agreed the sale of its assets in six Asian countries - including Hong Kong, Taiwan, Singapore and Vietnam - to Australia & New Zealand Banking Group for a price of around $550 million.
Written by Claire Archer